The development and deployment of Carbon dioxide Capture and Storage （CCS） technology is a cornerstone of the Norwegian government＇s climate strategy. A number of projects are currently evaluated/planned along the ...The development and deployment of Carbon dioxide Capture and Storage （CCS） technology is a cornerstone of the Norwegian government＇s climate strategy. A number of projects are currently evaluated/planned along the Norwegian West Coast, one at Tjeldbergodden. COe from this project will be utilized in part for enhanced oil recovery in the Halten oil field, in the Norwegian Sea. We study a potential design of such a system. A combined cycle power plant with a gross power output of 832 MW is combined with CO2 capture plant based on a post-combustion capture using amines as a solvent. The captured CO2 is used for enhanced oil recovery （EOR）. We employ a hybrid life-cycle assessment （LCA） method to assess the environmental impacts of the system. The study focuses on the modifications and operations of the platform during EOR. We allocate the impacts connected to the capture of CO2 to electricity production, and the impacts connected to the transport and storage of CO2 to the oil produced. Our study shows a substantial reduction of the greenhouse gas emissions from power production by 80% to 75 g·（kW·h）^-1. It also indicates a reduction of the emissions associated with oil production per unit oil produced, mostly due to the increased oil production. Reductions are especially significant if the additional power demand due to EOR leads to power supply from the land.展开更多
Esophageo-tracheal fistula is a rare condition,and in most cases such fistulas are caused by malignant disease or emergency endotracheal intubation.A case where a wrapped tablet produced a fistula between the esophagu...Esophageo-tracheal fistula is a rare condition,and in most cases such fistulas are caused by malignant disease or emergency endotracheal intubation.A case where a wrapped tablet produced a fistula between the esophagus and trachea is described.The patient is a male born in 1938 who swallowed a tablet without unwrapping it.The patient was treated with selfexpanding metal stents(SEMS),but closure of the fistula was not achieved.Different examinations and treatment options are discussed.Surgical treatment for this condition has demonstrated considerable mortality and morbidity.In some cases closure of the fistula can be achieved by use of SEMS.Although we advise treatment of such cases with SEMS,in some cases treatment with stents will prove troublesome and the risk/benefit analysis will have to be reevaluated.展开更多
Accurate measurement of the evolution of rock joint void geometry is essential for comprehending the distribution characteristics of asperities responsible for shear and seepage behaviors.However,existing techniques o...Accurate measurement of the evolution of rock joint void geometry is essential for comprehending the distribution characteristics of asperities responsible for shear and seepage behaviors.However,existing techniques often require specialized equipment and skilled operators,posing practical challenges.In this study,a cost-effective photogrammetric approach is proposed.Particularly,local coordinate systems are established to facilitate the alignment and precise quantification of the relative position between two halves of a rock joint.Push/pull tests are conducted on rock joints with varying roughness levels to induce different contact states.A high-precision laser scanner serves as a benchmark for evaluating the photogrammetry method.Despite certain deviations exist,the measured evolution of void geometry is generally consistent with the qualitative findings of previous studies.The photogrammetric measurements yield comparable accuracy to laser scanning,with maximum errors of 13.2%for aperture and 14.4%for void volume.Most joint matching coefficient(JMC)measurement errors are below 20%.Larger measurement errors occur primarily in highly mismatched rock joints with JMC values below 0.2,but even in cases where measurement errors exceed 80%,the maximum JMC error is only 0.0434.Thus,the proposed photogrammetric approach holds promise for widespread application in void geometry measurements in rock joints.展开更多
Teaching science through computer games,simulations,and artificial intelligence(AI)is an increasingly active research field.To this end,we conducted a systematic literature review on serious games for science educatio...Teaching science through computer games,simulations,and artificial intelligence(AI)is an increasingly active research field.To this end,we conducted a systematic literature review on serious games for science education to reveal research trends and patterns.We discussed the role of virtual reality(VR),AI,and augmented reality(AR)games in teaching science subjects like physics.Specifically,we covered the research spanning between 2011 and 2021,investigated country-wise concentration and most common evaluation methods,and discussed the positive and negative aspects of serious games in science education in particular and attitudes towards the use of serious games in education in general.展开更多
The Internet has become one of the significant sources for sharing information and expressing users’opinions about products and their interests with the associated aspects.It is essential to learn about product revie...The Internet has become one of the significant sources for sharing information and expressing users’opinions about products and their interests with the associated aspects.It is essential to learn about product reviews;however,to react to such reviews,extracting aspects of the entity to which these reviews belong is equally important.Aspect-based Sentiment Analysis(ABSA)refers to aspects extracted from an opinionated text.The literature proposes different approaches for ABSA;however,most research is focused on supervised approaches,which require labeled datasets with manual sentiment polarity labeling and aspect tagging.This study proposes a semisupervised approach with minimal human supervision to extract aspect terms by detecting the aspect categories.Hence,the study deals with two main sub-tasks in ABSA,named Aspect Category Detection(ACD)and Aspect Term Extraction(ATE).In the first sub-task,aspects categories are extracted using topic modeling and filtered by an oracle further,and it is fed to zero-shot learning as the prompts and the augmented text.The predicted categories are the input to find similar phrases curated with extracting meaningful phrases(e.g.,Nouns,Proper Nouns,NER(Named Entity Recognition)entities)to detect the aspect terms.The study sets a baseline accuracy for two main sub-tasks in ABSA on the Multi-Aspect Multi-Sentiment(MAMS)dataset along with SemEval-2014 Task 4 subtask 1 to show that the proposed approach helps detect aspect terms via aspect categories.展开更多
Objective.To study the prevalence of irritable bowel syndrome(IBS) and its comorbidity in a Norwegian adult popu-lation.Material and methods.In 2001,11,078 inhabitants(aged 30-75 years) in Oppland County were invited ...Objective.To study the prevalence of irritable bowel syndrome(IBS) and its comorbidity in a Norwegian adult popu-lation.Material and methods.In 2001,11,078 inhabitants(aged 30-75 years) in Oppland County were invited to take part in a public health survey.A total of 4622 subjects(42%) completed the questionnaires on symptoms of IBS(Rome II criteria) ,comorbidity,health-care visits and medications.The impact of comorbidity on global health,working disability and use of health-care resources in subjects with IBS was explored by stepwise logistic regression.Results.The population prevalence of IBS was 388/4622(8.4%(95% CI:7.6-9.4%) ) with a female predominance and an age-dependent decrease.The proportion who had consulted for IBS ranged from 51% among 30-year-olds to 79% in 75-year-olds(p =0.05) .IBS was associated with musculoskeletal complaints(OR = 2.4-3.4 for six different items) ,fibromyalgia(OR = 3.6 [2.7-4.8]) ,mood disorder(OR = 3.3(2.6-4.3) ) ,reduced global health(OR = 2.6(2.1-3.2) ) ,working disability(OR = 1.6(1.2-2.1) ) ,more frequent health-care visits and use of medications(OR 1.7-2.3) .When controlling for comorbidity,reduced global health(OR = 1.5(1.1-2.0) ) and use of alternative health care(OR = 1.7(1.3-2.4) ) remained associated with IBS.Severity of abdominal pain/discomfort was a predictor of having to seek a physician for IBS(OR = 1.3(1.2-1.5) ) .Conclusions.Symptoms of IBS were reported by 8% of Norwegian adults and had resulted in consultations with physicians for the majority in the long run.Subjects with IBS in the community were characterized by frequent somatic and psychiatric comorbidity.Their observed reduced health,working disability and increased use of health resources were largely explained by comorbid symptoms and disorders.展开更多
AIM To investigate if vitamin D deficiency is associated with fatigue in patients with inflammatory bowel disease(IBD).METHODS IBD patients were recruited from nine hospitals in the southeastern and western regions of...AIM To investigate if vitamin D deficiency is associated with fatigue in patients with inflammatory bowel disease(IBD).METHODS IBD patients were recruited from nine hospitals in the southeastern and western regions of Norway to participate in a multicenter cross-sectional study lasting from March 2013 to April 2014. Data were collected by interviews, from medical records and laboratory tests. The Fatigue Questionnaire(FQ) was used to measure fatigue. Linear and logistic regression models were applied to explore the possible association between vitamin D deficiency and total fatigue scores and chronic fatigue, respectively. The analyses were adjusted for age, gender, disease activity, depressive symptoms and sleep disturbance.RESULTS In total, 405 patients were included in the analyses, of which 227(56%) had Crohn's disease(CD) and 178(44%) had ulcerative colitis(UC). Vitamin D deficiency(< 50 nmol/L) was present in half(203/405) of the patients. Chronic fatigue was reported by 116(29%) of all included patients with substantial fatigue reported by 194(48%). Vitamin D levels were neither associated with total fatigue nor with chronic fatigue. Higher total fatigue scores and chronic fatigue were both associated with increased disease activity scores in patients with UC and CD, but not with increased CRP or fecal calprotectin. In UC patients, female gender was associated with fatigue in the univariate analysis, but no such difference was found when adjusted for elevated disease activity scores. Sleep disturbance and more depressive symptoms were associated with total fatigue scores in both UC and CD patients, but with chronic fatigue only in CD patients.CONCLUSION In this study, no significant association between fatigue and vitamin D deficiency in IBD patients was revealed.展开更多
Battery systems are increasingly being used for powering ocean going ships,and the number of fully electric or hybrid ships relying on battery power for propulsion is growing.To ensure the safety of such ships,it is i...Battery systems are increasingly being used for powering ocean going ships,and the number of fully electric or hybrid ships relying on battery power for propulsion is growing.To ensure the safety of such ships,it is important to monitor the available energy that can be stored in the batteries,and classification societies typically require the state of health(SOH)to be verified by independent tests.This paper addresses statistical modeling of SOH for maritime lithium-ion batteries based on operational sensor data.Various methods for sensor-based,data-driven degradation monitoring will be presented,and advantages and challenges with the different approaches will be discussed.The different approaches include cumulative degradation models and snapshot models,models that need to be trained and models that need no prior training,and pure data-driven models and physics-informed models.Some of the methods only rely on measured data,such as current,voltage,and temperature,whereas others rely on derived quantities such as state of charge.Models include simple statistical models and more complicated machine learning techniques.Insight from this exploration will be important in establishing a framework for data-driven diagnostics and prognostics of maritime battery systems within the scope of classification societies.展开更多
An actuator is a machine or component installed on the top of an industrial valve for automatically moving and controlling the valve.The performance of a valve is largely dependent on its actuator.An actuator can be h...An actuator is a machine or component installed on the top of an industrial valve for automatically moving and controlling the valve.The performance of a valve is largely dependent on its actuator.An actuator can be hydraulic,pneumatic,or electrical.This paper focuses on hydraulic actuators,which are common for large size and high-pressure class ball valves.Hydraulic actuators can be either single-acting(spring return)or double-acting.Single-acting actuators return to safe mode in case of failure.However,double-acting actuators have a fail-as-is function and cannot keep the valves open or closed in case of failure.This research used a combination of theoretical and experimental approaches.The paper discusses two case studies in offshore industry projects in which double-acting hydraulic actuators were selected instead of single-acting,and possible design impacts are discussed.A theoretical review is given in three papers about operating torque for ball valves,optimization of shutdown valve actuator weight,and design and analysis of hydraulic actuators.These three papers were selected for review to connect the valve required torque with actuator sizing and selection,finding practical approaches to optimize the actuator weight as well as develop a theoretical model to calculate the actuator thickness and dimensions for the 38”CL1500 ball valve in the Johan Sverdrup project.The proposed formulas and calculations used for sizing the 38”CL1500 ball valves were validated through a finite element analysis model.展开更多
Monel K-500 is a Ni–Cu alloy widely used in the marine and offshore industry due to their superior resistance to corrosion in seawater and hence easily degraded.To address this problem,laser-based directed energy dep...Monel K-500 is a Ni–Cu alloy widely used in the marine and offshore industry due to their superior resistance to corrosion in seawater and hence easily degraded.To address this problem,laser-based directed energy deposition(LDED)is used to repair or refabricate these high-value worn parts.To optimize the mechanical properties of repaired parts,the commonly applied solution and aging is not ideal because it also changes the properties of the base materials.Consequently,in situ control of the grain structures during the LDED process becomes an effective approach for high-performance repair.In this study,we fabricated a duplex grain structure with small grain size and low texture intensity using low laser power and scanning velocity.The duplex microstructure consists of short columnar grains and zigzag-distributed fine equiaxed grains.The formation of this grain structure is dependent on both the solidification and recrystallization mechanisms.The strength of this grain structure is improved to 523.5 MPa without the sacrifice of ductility,which is instead 20%higher than that of the counterpart consisting of typical columnar grains due to the grain refinement and crack toughening.The mechanical properties of the alloy with the duplex grain structure are even comparable to heat-treated Monel K-500 fabricated by wire arc additive manufacturing.This work provides valuable insights into the in situ optimization of the microstructure and mechanical properties of LDED-fabricated parts.展开更多
In Norway,300,000 people attend higher education.Elsewhere in Europe,student numbers are also high.In Great Britain,1.9 million people attended higher education in the academic year 2018–2019.This is a substantial pa...In Norway,300,000 people attend higher education.Elsewhere in Europe,student numbers are also high.In Great Britain,1.9 million people attended higher education in the academic year 2018–2019.This is a substantial part of the population,and the mental health and well-being of students are of prime importance.Thefirst year as a university student is a transitional period characterized by significant changes and constitutes an essential fundament for students in their student life and later.An increasing number of students report having mental health problems to various degrees.Identifying the variety of perceptions of what may promote mental health and well-being is therefore of importance.This study aims to explore whetherfirst year students in higher education perceive student life as promoting their mental health and well-being.Twenty students were interviewed(n=20).Phenomenographic analysis was used to reveal variation in the students’perceptions.Two descriptive categories were constructed,“The need to belong”and“The need for support,”withfive conceptions:the importance of the sponsorship week,small groups as a place to belong,being patient,a supportive environment and the university as a facilitator.How a sense of belonging and a sense of support was achieved varied among the participants,and the solution for how to achieve this lies in the students themselves,the way the university organizes the programmes and how the students are met by the administration,lecturers and fellow students.展开更多
Purpose: This study reports the reliability and validity analyses of the Audit on diabetes-dependent quality of life (ADDQoL) and EQ-5D in elderly Slovenian diabetic patients. Methods: A cross-sectional study of elder...Purpose: This study reports the reliability and validity analyses of the Audit on diabetes-dependent quality of life (ADDQoL) and EQ-5D in elderly Slovenian diabetic patients. Methods: A cross-sectional study of elderly (age ≥ 65 years) non-insulin dependent diabetes mellitus type 2 (DMT2) patients was carried out. The ADDQoL and EQ-5D surveys were conducted between January and May, 2012. Statistical analysis was performed using IBM SPSS Statistics software, version 20.0. Results: After exclusion of non-eligible respondents, the final sample for the analysis was 261 cases (51% male), resulting in 52.2%of response rate. The mean age of the patients was 70.3 years (SD ± 4.1). The Cronbach’s alpha was 0.93 for ADDQoL and 0.73 for EQ-5D.There was no improvement in the alpha value if any item was deleted in all instruments. Missing value items ranged from 0.8% to 1.5% for EQ-5D, and from 0.8% to 59.1% (working life) in ADDQoL. Spearman’s correlation between the EQ-5D VAS score and ADDQoL weighted overall score resulted in weak correlations coefficient (r = 0.294;p < 0.001). Conclusions: The ADDQoL proved reliable and valid for assessing Health Related Quality of Life (HRQoL) among elderly Slovenian DMT2 patients. EQ-5D seemed to be too generic to describe limitations of DMT2 patients in detail. Using disease specific QoL instruments to learn about patient limitations was recommended. Comparison of ADDQoL results between various studies provided significant differences in the impact of diabetes.展开更多
Water covers most of the Earth’s surface and is nowhere near a good ecological or recreational state in many areas of the world.Moreover,only a small fraction of the water is potable.As climate change-induced extreme...Water covers most of the Earth’s surface and is nowhere near a good ecological or recreational state in many areas of the world.Moreover,only a small fraction of the water is potable.As climate change-induced extreme weather events become ever more prevalent,more and more issues arise,such as worsening water quality problems.Therefore,protecting invaluable and useable drinking water is critical.Environmental agencies must continuously check water sources to determine whether they are in a good or healthy state regarding pollutant levels and ecological status.The currently available tools are better suited for stationary laboratory use,and domain specialists lack suitable tools for onsite visualisation and interactive exploration of environmental data.Meanwhile,data collection for laboratory analysis requires substantial time and significant effort.We,therefore,developed an augmented reality system with a Microsoft HoloLens 2 device to explore the visualisation of water quality and status in situ.The developed prototype visualises geo-referenced sensor measurements incorporated into the perspective of the surroundings.Any users interested in water bodies’conditions can quickly examine and retrieve an overview of water body status using augmented reality and then take necessary steps to address the current situation.展开更多
Global climate change may have serious impact on human activities in coastal and other areas.Climate change may affect the degree of storminess and,hence,change the wind-driven ocean wave climate.This may affect the r...Global climate change may have serious impact on human activities in coastal and other areas.Climate change may affect the degree of storminess and,hence,change the wind-driven ocean wave climate.This may affect the risks associated with maritime activities such as shipping and offshore oil and gas.So,there is a recognized need to understand better how climate change will affect such processes.Typically,such understanding comes from future projections of the wind and wave climate from numerical climate models and from the stochastic modelling of such projections.This work investigates the applicability of a recently proposed nonstationary fuzzy modelling to wind and wave climatic simulations.According to this,fuzzy inference models(FIS)are coupled with nonstationary time series modelling,providing us with less biased climatic estimates.Two long-term datasets for an area in the North Atlantic Ocean are used in the present study,namely NORA10(57 years)and ExWaCli(30 years in the present and 30 years in the future).Two distinct experiments have been performed to simulate future values of the time series in a climatic scale.The assessment of the simulations by means of the actual values kept for comparison purposes gives very good results.展开更多
There are increasing focuses on developing cost-effective floating wind turbines,for which efficient stress analysis methods are needed for floater structural design.Most of the today’s studies focus on global analys...There are increasing focuses on developing cost-effective floating wind turbines,for which efficient stress analysis methods are needed for floater structural design.Most of the today’s studies focus on global analysis methods in which the floater is assumed as a rigid body or multiple rigid bodies and the stress distributions in the floater cannot be directly obtained.As part of the COWI Fonden funded EMULF project,a summary about the methodology,the numerical modeling procedure and the verification for stress response analysis of a semi-submersible floater for a 15MW wind turbine is presented.This analy-sis procedure includes the regeneration of the hydrodynamic pressure loads on the external wet surface of the floater due to wave diffraction,radiation and hydrostatic pressure change,and the application of these pressure loads,together with the time-varying gravity due motions,the inertial loads and the forces/moments at the boundaries(i.e.tower bottom and mooring line fairleads)of the floater to obtain the deformation and the stresses of the floater in the time domain.The analysis procedure is imple-mented in a developed MATLAB code and the DNV software package.The importance of the different hydrodynamic pressure components was discussed considering representative sea states.A verification of the obtained stress time series and statistics using this method against the regeneration from a linear frequency-domain approach was made considering irregular wave actions only,and a very good agree-ment was obtained.The developed methodology can provide an efficient solution for structural design analysis of floating wind turbines.展开更多
One of the major concerns regarding currently proposed public blockchain systems relates to the feasible transaction processing rate.It is common for such systems to limit this rate to maintain the required levels of ...One of the major concerns regarding currently proposed public blockchain systems relates to the feasible transaction processing rate.It is common for such systems to limit this rate to maintain the required levels of security and decentralisation.State channels are an approach to overcome this limitation,as they aim to decrease the required on-chain transactions for a given application and thus indirectly increase the capacity(in terms of applications)of public blockchain systems.In the present paper,we propose a state channel design that,through the use of RSA accumulators,operates on a compact state structure.This scheme is optimal for applications whose state includes large sets of elements.The novel state channel design is presented by analysing all state channel operations and how they have to be revised.The security of the design is discussed,while a practical use case scenario regarding the use of the design for an on-chain asset(e.g.,non-fungible tokens)exchange application is also analysed.展开更多
文摘The development and deployment of Carbon dioxide Capture and Storage （CCS） technology is a cornerstone of the Norwegian government＇s climate strategy. A number of projects are currently evaluated/planned along the Norwegian West Coast, one at Tjeldbergodden. COe from this project will be utilized in part for enhanced oil recovery in the Halten oil field, in the Norwegian Sea. We study a potential design of such a system. A combined cycle power plant with a gross power output of 832 MW is combined with CO2 capture plant based on a post-combustion capture using amines as a solvent. The captured CO2 is used for enhanced oil recovery （EOR）. We employ a hybrid life-cycle assessment （LCA） method to assess the environmental impacts of the system. The study focuses on the modifications and operations of the platform during EOR. We allocate the impacts connected to the capture of CO2 to electricity production, and the impacts connected to the transport and storage of CO2 to the oil produced. Our study shows a substantial reduction of the greenhouse gas emissions from power production by 80% to 75 g·（kW·h）^-1. It also indicates a reduction of the emissions associated with oil production per unit oil produced, mostly due to the increased oil production. Reductions are especially significant if the additional power demand due to EOR leads to power supply from the land.
文摘Esophageo-tracheal fistula is a rare condition,and in most cases such fistulas are caused by malignant disease or emergency endotracheal intubation.A case where a wrapped tablet produced a fistula between the esophagus and trachea is described.The patient is a male born in 1938 who swallowed a tablet without unwrapping it.The patient was treated with selfexpanding metal stents(SEMS),but closure of the fistula was not achieved.Different examinations and treatment options are discussed.Surgical treatment for this condition has demonstrated considerable mortality and morbidity.In some cases closure of the fistula can be achieved by use of SEMS.Although we advise treatment of such cases with SEMS,in some cases treatment with stents will prove troublesome and the risk/benefit analysis will have to be reevaluated.
基金supported by the National Natural Science Foundation of China (Nos.42207175 and 42177117)the Ningbo Natural Science Foundation (No.2022J115)。
文摘Accurate measurement of the evolution of rock joint void geometry is essential for comprehending the distribution characteristics of asperities responsible for shear and seepage behaviors.However,existing techniques often require specialized equipment and skilled operators,posing practical challenges.In this study,a cost-effective photogrammetric approach is proposed.Particularly,local coordinate systems are established to facilitate the alignment and precise quantification of the relative position between two halves of a rock joint.Push/pull tests are conducted on rock joints with varying roughness levels to induce different contact states.A high-precision laser scanner serves as a benchmark for evaluating the photogrammetry method.Despite certain deviations exist,the measured evolution of void geometry is generally consistent with the qualitative findings of previous studies.The photogrammetric measurements yield comparable accuracy to laser scanning,with maximum errors of 13.2%for aperture and 14.4%for void volume.Most joint matching coefficient(JMC)measurement errors are below 20%.Larger measurement errors occur primarily in highly mismatched rock joints with JMC values below 0.2,but even in cases where measurement errors exceed 80%,the maximum JMC error is only 0.0434.Thus,the proposed photogrammetric approach holds promise for widespread application in void geometry measurements in rock joints.
文摘Teaching science through computer games,simulations,and artificial intelligence(AI)is an increasingly active research field.To this end,we conducted a systematic literature review on serious games for science education to reveal research trends and patterns.We discussed the role of virtual reality(VR),AI,and augmented reality(AR)games in teaching science subjects like physics.Specifically,we covered the research spanning between 2011 and 2021,investigated country-wise concentration and most common evaluation methods,and discussed the positive and negative aspects of serious games in science education in particular and attitudes towards the use of serious games in education in general.
文摘The Internet has become one of the significant sources for sharing information and expressing users’opinions about products and their interests with the associated aspects.It is essential to learn about product reviews;however,to react to such reviews,extracting aspects of the entity to which these reviews belong is equally important.Aspect-based Sentiment Analysis(ABSA)refers to aspects extracted from an opinionated text.The literature proposes different approaches for ABSA;however,most research is focused on supervised approaches,which require labeled datasets with manual sentiment polarity labeling and aspect tagging.This study proposes a semisupervised approach with minimal human supervision to extract aspect terms by detecting the aspect categories.Hence,the study deals with two main sub-tasks in ABSA,named Aspect Category Detection(ACD)and Aspect Term Extraction(ATE).In the first sub-task,aspects categories are extracted using topic modeling and filtered by an oracle further,and it is fed to zero-shot learning as the prompts and the augmented text.The predicted categories are the input to find similar phrases curated with extracting meaningful phrases(e.g.,Nouns,Proper Nouns,NER(Named Entity Recognition)entities)to detect the aspect terms.The study sets a baseline accuracy for two main sub-tasks in ABSA on the Multi-Aspect Multi-Sentiment(MAMS)dataset along with SemEval-2014 Task 4 subtask 1 to show that the proposed approach helps detect aspect terms via aspect categories.
文摘Objective.To study the prevalence of irritable bowel syndrome(IBS) and its comorbidity in a Norwegian adult popu-lation.Material and methods.In 2001,11,078 inhabitants(aged 30-75 years) in Oppland County were invited to take part in a public health survey.A total of 4622 subjects(42%) completed the questionnaires on symptoms of IBS(Rome II criteria) ,comorbidity,health-care visits and medications.The impact of comorbidity on global health,working disability and use of health-care resources in subjects with IBS was explored by stepwise logistic regression.Results.The population prevalence of IBS was 388/4622(8.4%(95% CI:7.6-9.4%) ) with a female predominance and an age-dependent decrease.The proportion who had consulted for IBS ranged from 51% among 30-year-olds to 79% in 75-year-olds(p =0.05) .IBS was associated with musculoskeletal complaints(OR = 2.4-3.4 for six different items) ,fibromyalgia(OR = 3.6 [2.7-4.8]) ,mood disorder(OR = 3.3(2.6-4.3) ) ,reduced global health(OR = 2.6(2.1-3.2) ) ,working disability(OR = 1.6(1.2-2.1) ) ,more frequent health-care visits and use of medications(OR 1.7-2.3) .When controlling for comorbidity,reduced global health(OR = 1.5(1.1-2.0) ) and use of alternative health care(OR = 1.7(1.3-2.4) ) remained associated with IBS.Severity of abdominal pain/discomfort was a predictor of having to seek a physician for IBS(OR = 1.3(1.2-1.5) ) .Conclusions.Symptoms of IBS were reported by 8% of Norwegian adults and had resulted in consultations with physicians for the majority in the long run.Subjects with IBS in the community were characterized by frequent somatic and psychiatric comorbidity.Their observed reduced health,working disability and increased use of health resources were largely explained by comorbid symptoms and disorders.
文摘AIM To investigate if vitamin D deficiency is associated with fatigue in patients with inflammatory bowel disease(IBD).METHODS IBD patients were recruited from nine hospitals in the southeastern and western regions of Norway to participate in a multicenter cross-sectional study lasting from March 2013 to April 2014. Data were collected by interviews, from medical records and laboratory tests. The Fatigue Questionnaire(FQ) was used to measure fatigue. Linear and logistic regression models were applied to explore the possible association between vitamin D deficiency and total fatigue scores and chronic fatigue, respectively. The analyses were adjusted for age, gender, disease activity, depressive symptoms and sleep disturbance.RESULTS In total, 405 patients were included in the analyses, of which 227(56%) had Crohn's disease(CD) and 178(44%) had ulcerative colitis(UC). Vitamin D deficiency(< 50 nmol/L) was present in half(203/405) of the patients. Chronic fatigue was reported by 116(29%) of all included patients with substantial fatigue reported by 194(48%). Vitamin D levels were neither associated with total fatigue nor with chronic fatigue. Higher total fatigue scores and chronic fatigue were both associated with increased disease activity scores in patients with UC and CD, but not with increased CRP or fecal calprotectin. In UC patients, female gender was associated with fatigue in the univariate analysis, but no such difference was found when adjusted for elevated disease activity scores. Sleep disturbance and more depressive symptoms were associated with total fatigue scores in both UC and CD patients, but with chronic fatigue only in CD patients.CONCLUSION In this study, no significant association between fatigue and vitamin D deficiency in IBD patients was revealed.
基金This work has been carried out with in the DDD BATMAN project,supported by MarTERA and the Research Council of Norway(project no 311445).
文摘Battery systems are increasingly being used for powering ocean going ships,and the number of fully electric or hybrid ships relying on battery power for propulsion is growing.To ensure the safety of such ships,it is important to monitor the available energy that can be stored in the batteries,and classification societies typically require the state of health(SOH)to be verified by independent tests.This paper addresses statistical modeling of SOH for maritime lithium-ion batteries based on operational sensor data.Various methods for sensor-based,data-driven degradation monitoring will be presented,and advantages and challenges with the different approaches will be discussed.The different approaches include cumulative degradation models and snapshot models,models that need to be trained and models that need no prior training,and pure data-driven models and physics-informed models.Some of the methods only rely on measured data,such as current,voltage,and temperature,whereas others rely on derived quantities such as state of charge.Models include simple statistical models and more complicated machine learning techniques.Insight from this exploration will be important in establishing a framework for data-driven diagnostics and prognostics of maritime battery systems within the scope of classification societies.
文摘An actuator is a machine or component installed on the top of an industrial valve for automatically moving and controlling the valve.The performance of a valve is largely dependent on its actuator.An actuator can be hydraulic,pneumatic,or electrical.This paper focuses on hydraulic actuators,which are common for large size and high-pressure class ball valves.Hydraulic actuators can be either single-acting(spring return)or double-acting.Single-acting actuators return to safe mode in case of failure.However,double-acting actuators have a fail-as-is function and cannot keep the valves open or closed in case of failure.This research used a combination of theoretical and experimental approaches.The paper discusses two case studies in offshore industry projects in which double-acting hydraulic actuators were selected instead of single-acting,and possible design impacts are discussed.A theoretical review is given in three papers about operating torque for ball valves,optimization of shutdown valve actuator weight,and design and analysis of hydraulic actuators.These three papers were selected for review to connect the valve required torque with actuator sizing and selection,finding practical approaches to optimize the actuator weight as well as develop a theoretical model to calculate the actuator thickness and dimensions for the 38”CL1500 ball valve in the Johan Sverdrup project.The proposed formulas and calculations used for sizing the 38”CL1500 ball valves were validated through a finite element analysis model.
基金supported by Economic Development Board,Singapore and DNV Singapore Pte.Ltd.through Industrial Postgraduate Programme with Nanyang Technological University,Singapore,and the National Research Foundation,Prime Minister's Office,Singapore under its Medium-Sized Centre funding scheme through the Marine and Offshore Program.
文摘Monel K-500 is a Ni–Cu alloy widely used in the marine and offshore industry due to their superior resistance to corrosion in seawater and hence easily degraded.To address this problem,laser-based directed energy deposition(LDED)is used to repair or refabricate these high-value worn parts.To optimize the mechanical properties of repaired parts,the commonly applied solution and aging is not ideal because it also changes the properties of the base materials.Consequently,in situ control of the grain structures during the LDED process becomes an effective approach for high-performance repair.In this study,we fabricated a duplex grain structure with small grain size and low texture intensity using low laser power and scanning velocity.The duplex microstructure consists of short columnar grains and zigzag-distributed fine equiaxed grains.The formation of this grain structure is dependent on both the solidification and recrystallization mechanisms.The strength of this grain structure is improved to 523.5 MPa without the sacrifice of ductility,which is instead 20%higher than that of the counterpart consisting of typical columnar grains due to the grain refinement and crack toughening.The mechanical properties of the alloy with the duplex grain structure are even comparable to heat-treated Monel K-500 fabricated by wire arc additive manufacturing.This work provides valuable insights into the in situ optimization of the microstructure and mechanical properties of LDED-fabricated parts.
文摘In Norway,300,000 people attend higher education.Elsewhere in Europe,student numbers are also high.In Great Britain,1.9 million people attended higher education in the academic year 2018–2019.This is a substantial part of the population,and the mental health and well-being of students are of prime importance.Thefirst year as a university student is a transitional period characterized by significant changes and constitutes an essential fundament for students in their student life and later.An increasing number of students report having mental health problems to various degrees.Identifying the variety of perceptions of what may promote mental health and well-being is therefore of importance.This study aims to explore whetherfirst year students in higher education perceive student life as promoting their mental health and well-being.Twenty students were interviewed(n=20).Phenomenographic analysis was used to reveal variation in the students’perceptions.Two descriptive categories were constructed,“The need to belong”and“The need for support,”withfive conceptions:the importance of the sponsorship week,small groups as a place to belong,being patient,a supportive environment and the university as a facilitator.How a sense of belonging and a sense of support was achieved varied among the participants,and the solution for how to achieve this lies in the students themselves,the way the university organizes the programmes and how the students are met by the administration,lecturers and fellow students.
文摘Purpose: This study reports the reliability and validity analyses of the Audit on diabetes-dependent quality of life (ADDQoL) and EQ-5D in elderly Slovenian diabetic patients. Methods: A cross-sectional study of elderly (age ≥ 65 years) non-insulin dependent diabetes mellitus type 2 (DMT2) patients was carried out. The ADDQoL and EQ-5D surveys were conducted between January and May, 2012. Statistical analysis was performed using IBM SPSS Statistics software, version 20.0. Results: After exclusion of non-eligible respondents, the final sample for the analysis was 261 cases (51% male), resulting in 52.2%of response rate. The mean age of the patients was 70.3 years (SD ± 4.1). The Cronbach’s alpha was 0.93 for ADDQoL and 0.73 for EQ-5D.There was no improvement in the alpha value if any item was deleted in all instruments. Missing value items ranged from 0.8% to 1.5% for EQ-5D, and from 0.8% to 59.1% (working life) in ADDQoL. Spearman’s correlation between the EQ-5D VAS score and ADDQoL weighted overall score resulted in weak correlations coefficient (r = 0.294;p < 0.001). Conclusions: The ADDQoL proved reliable and valid for assessing Health Related Quality of Life (HRQoL) among elderly Slovenian DMT2 patients. EQ-5D seemed to be too generic to describe limitations of DMT2 patients in detail. Using disease specific QoL instruments to learn about patient limitations was recommended. Comparison of ADDQoL results between various studies provided significant differences in the impact of diabetes.
基金supported by the Freshwater Competence Centre,Academy of Finland(Decision No.345008)the Nordic University Cooperation on Edge Intelligence(Grant No.168043).
文摘Water covers most of the Earth’s surface and is nowhere near a good ecological or recreational state in many areas of the world.Moreover,only a small fraction of the water is potable.As climate change-induced extreme weather events become ever more prevalent,more and more issues arise,such as worsening water quality problems.Therefore,protecting invaluable and useable drinking water is critical.Environmental agencies must continuously check water sources to determine whether they are in a good or healthy state regarding pollutant levels and ecological status.The currently available tools are better suited for stationary laboratory use,and domain specialists lack suitable tools for onsite visualisation and interactive exploration of environmental data.Meanwhile,data collection for laboratory analysis requires substantial time and significant effort.We,therefore,developed an augmented reality system with a Microsoft HoloLens 2 device to explore the visualisation of water quality and status in situ.The developed prototype visualises geo-referenced sensor measurements incorporated into the perspective of the surroundings.Any users interested in water bodies’conditions can quickly examine and retrieve an overview of water body status using augmented reality and then take necessary steps to address the current situation.
文摘Global climate change may have serious impact on human activities in coastal and other areas.Climate change may affect the degree of storminess and,hence,change the wind-driven ocean wave climate.This may affect the risks associated with maritime activities such as shipping and offshore oil and gas.So,there is a recognized need to understand better how climate change will affect such processes.Typically,such understanding comes from future projections of the wind and wave climate from numerical climate models and from the stochastic modelling of such projections.This work investigates the applicability of a recently proposed nonstationary fuzzy modelling to wind and wave climatic simulations.According to this,fuzzy inference models(FIS)are coupled with nonstationary time series modelling,providing us with less biased climatic estimates.Two long-term datasets for an area in the North Atlantic Ocean are used in the present study,namely NORA10(57 years)and ExWaCli(30 years in the present and 30 years in the future).Two distinct experiments have been performed to simulate future values of the time series in a climatic scale.The assessment of the simulations by means of the actual values kept for comparison purposes gives very good results.
文摘There are increasing focuses on developing cost-effective floating wind turbines,for which efficient stress analysis methods are needed for floater structural design.Most of the today’s studies focus on global analysis methods in which the floater is assumed as a rigid body or multiple rigid bodies and the stress distributions in the floater cannot be directly obtained.As part of the COWI Fonden funded EMULF project,a summary about the methodology,the numerical modeling procedure and the verification for stress response analysis of a semi-submersible floater for a 15MW wind turbine is presented.This analy-sis procedure includes the regeneration of the hydrodynamic pressure loads on the external wet surface of the floater due to wave diffraction,radiation and hydrostatic pressure change,and the application of these pressure loads,together with the time-varying gravity due motions,the inertial loads and the forces/moments at the boundaries(i.e.tower bottom and mooring line fairleads)of the floater to obtain the deformation and the stresses of the floater in the time domain.The analysis procedure is imple-mented in a developed MATLAB code and the DNV software package.The importance of the different hydrodynamic pressure components was discussed considering representative sea states.A verification of the obtained stress time series and statistics using this method against the regeneration from a linear frequency-domain approach was made considering irregular wave actions only,and a very good agree-ment was obtained.The developed methodology can provide an efficient solution for structural design analysis of floating wind turbines.
文摘One of the major concerns regarding currently proposed public blockchain systems relates to the feasible transaction processing rate.It is common for such systems to limit this rate to maintain the required levels of security and decentralisation.State channels are an approach to overcome this limitation,as they aim to decrease the required on-chain transactions for a given application and thus indirectly increase the capacity(in terms of applications)of public blockchain systems.In the present paper,we propose a state channel design that,through the use of RSA accumulators,operates on a compact state structure.This scheme is optimal for applications whose state includes large sets of elements.The novel state channel design is presented by analysing all state channel operations and how they have to be revised.The security of the design is discussed,while a practical use case scenario regarding the use of the design for an on-chain asset(e.g.,non-fungible tokens)exchange application is also analysed.
